Thiadiazolyl and benzothiazolylureas are taught as herbicides in patents such as U.S. Pat. Nos. 4,412,079 and 2,756,135 and British Patent No. 1,254,468. Carbamates and carbamate derivatives, such as carbamoyloximes, are taught as insecticides in patents such as U.S. Pat. Nos. 3,313,684, 2,903,478, 3,474,170, and 3,217,037. The preparation of these herbicidal and insecticidal compounds generally requires the use of rather dangerous reactants such as phosgene or an isocyanate such as methylisocyanate or the like. These reactants, especially the isocyanates, are well known as highly toxic substances, as evidenced by the recent industrial accident involving the release of methylisocyanate into the atmosphere, resulting in great injury and loss of human life.
An object of this invention is to provide a process for preparing herbicidal ureas and insecticidal carbamates and carbamate derivatives which obviates the need to use dangerous reactants such as an isocyanate or phosgene. Accordingly, the present invention provides a process for preparing herbicidal thiadiazolyl and benzothiazolylureas and insecticidal carbamates and carbamoyloximes by reacting a nucleophile, such as an amine, alcohol, or oxime, with a urea in an inert solvent.